Guys,
I'm a bit late following this thread. My guess was that it was a local dealer mod too, which Holeshot has confirmed w his contact in Geelong. No doubt it had a 'factory look'. Lyall O'Brien did things very well. (Not long before he died he sent me copies of dyno curves of 360 (46M) engines that he was getting 50hp from, modifed for road-racing w 6-port engines etc). He was a wiz.
The way the factory did the V75 (& 54M enduro) was much different as Jared pointed out. Very different top shock mount, different frame loop over rear guard, & no diagonal bracing up towards the front of the seat.
The original VR had noticeably inward canted shocks from the factory (ie bottom mounts considerably wider than top mounts). Magazine tests of the day pointed out that strange feature. The V75 (& 54M) did not have that.
To my mind, the VR engine is the killer engine of the class (pre75). DirtBike mag certainly rated it so; better than a 'snore, YZ, Penton etc. MAG Husky was fairly mild by comparison too. The only thing they reckon came close to the 74VR was the 73VR. The 74VR used an unbridged exhaust port with considerably more radical timing than the bridged port of the 73. Diff pipe too. I have compared the porting specs of numerous pre75 250 engines & the VR barrell (esp 74) is much more radical on exh & transfer timing, but very mild on intake duration. (Its one reason they still got a broad powerband) So if you want more power... start w the inlet, which just happens to be the easiest to modify too.
Pretty bikes too, as mentioned above. So is the VA125. I had a VB 125, but they're not as pretty as the VA125. Bigends are weak in both. Just like in the original 18M 125 Cappra of 71-73. I seem to recall Lyall O'brien telling me you can replace the bigend w a standard size ING brg & even keeping the std rod the reliabilty problems vanish. Probably applies to both 4sp & 6sp 125 cappra engines.
My V75 has an ING brg in it now & those brgs have more rollers in them than the std Mon brg. ING brg rated to 21,000 rpm too! Pity I haven't completed the rebuild yet.
Somebody above was asking about shock length for VR. Koni shocks listed in an Old Bike Journal I have indicate 13" for VR & V75.. Personally I'd run 13.5" tho.
Great bikes. Enjoy!
